Application of Advanced Constitutive Models to the Simulation of Machining

Advanced constitutive models have long been used to describe plastic material response at high strains and high strain rates. These models include the Johnson-Cook, Zerrelli-Armstrong and Material Threshold Stress (MTS) formulations, each with a separate fidelity. The constitutive parameters for these complex models are commonly identified using laboratory techniques such as quasi-static load frames at room and elevated temperatures, Split Hopkinson Pressure Bars (SHPB) in tension and compression, gas guns, and Taylor impact cylinders. However, while the models are able to adequately describe material response under high strain and high strain rate, the loadings are all uniaxial in nature. The ability of these constitutive models and parameters to describe a different dynamic loading event, namely shear dominated machining, has not been thoroughly investigated. This work will develop numerical simulations applying multiple constitutive models with material parameters experimentally determined for fully annealed copper samples. Ultimately, the machining simulation will be compared with high fidelity experimental machining data. The utility of this research extends to the fundamental questions that surround the machining process, such as tool forces, surface damage, precision and quality.